Re: [tlug] Dell Dimension-C Autopsy: Mo' bulged electrolytic capacitors

[Jim <jep200404@example.com>]

For those who missed the background on bad caps: 

   http://www.google.com/search?q=site%3Acolug.net+capacitors

"Lyle (Hiroshi) Saxon" <ronfaxon@example.com> wrote:

> I disassembled my dead Dell Dimension-C and did an autopsy. 

> Capacitors....

Welcome to the club. 

> In my old machine (bought new in... 2000.... 

2000 was right in the thick of the bad cap era. 

> one of them [bad cap] leaked a very dark 
> brown goo that flowed about 8cm across the main circuit board - that's 
> probably the detail that stopped the board from functioning.

The presence of the goo on the board is likely _not_ what caused 
the board to fail. The _absence_ of the goo from the inside of the 
cap is what caused the board to fail. _Most_ of the bad caps I've 
seen did _not_ leak. 

> Taking a close look at the underside of the circuit board I see that the 
> contact area for the capacitor pins is very small (having been soldered 
> by a machine, not human hands) 

People can solder those small pads with no difficulty. 

> and would require a proper soldering iron 
> at a proper temperature, with the proper very narrow tip size and - last 
> but not least - steady and careful hands and skillful application of 
> heat. 

It's less sophisticated than you think. Because the caps are 
substantial heat sinks themselves, and because the power planes 
are even better heat sinks, one typically uses a hotter than 
usual soldering iron but applies it very briefly. With practice, 
the application of heat is brief. I usually unsolder both leads 
of a bad cap simultaneously. 

> The Dell Dimension-C is the second Dell I've had to go suddenly 
> dead on me, so I've developed a slight Dell allergy 

Keep in mind that many many manufacturers, including 
prestigious high-quality ones, suffered from the bad cap problem. 
I'm not keen of Dell computers, but I wouldn't pick on Dell much 
about this problem, because Dell had much company in this misery. 

Jim